The present invention relates to a water spray gun, and more specifically to a detergent/water mixing system for a water spray gun.
FIG. 1 shows a structure of water spray gun according to U.S. Pat. No. 4,785,850. According to this design, a control valve 1 is rotated to close/open the passage between a water inlet 2 and a water outlet 3, and a detergent container means 4 is attached to the casing of the water spray gun at the bottom side. The container means 4 has two through holes 4A;4B respectively disposed in communication with the water inlet 2 and the water outlet 3. When water passes from the water inlet 2 through a narrow water hole 1A on the control valve 1 to the water outlet 3, a part of water flows through one through hole 4A into the container means 4 and then flows out of the container means 4 through the other through hole 4B to carry detergent out of the container means 4 to the water outlet 3. This design has drawbacks. Because the diameter of the water hole 1A on the control valve 1 is much smaller than that of the water inlet 2, the flowing speed of water is accelerated when passing through the water hole 1A, and less amount of water is capable of flowing through the through hole 4A into the container means 4. Further, the rapid flow of water which passes through the water hole 1A of the control valve 1 into the water outlet 3 produces an upward suction force, causing high concentration detergent solution to be rapidly carried out of the container means 4 into the water outlet 3, i.e., detergent solution is not well mixed with water in the container means 4 before it is carried out of the container means 4 into the water outlet 3.